Fix memory leak in postgresql_extensible

CHANGELOG.md

@@ -5,6 +5,7 @@
 - [#3729](https://github.com/influxdata/telegraf/issues/3729): Set path to / if HOST_MOUNT_PREFIX matches full path.
 - [#3739](https://github.com/influxdata/telegraf/issues/3739): Remove userinfo from url tag in prometheus input.
 - [#3778](https://github.com/influxdata/telegraf/issues/3778): Fix ping plugin not reporting zero durations.
+- [#3807](https://github.com/influxdata/telegraf/issues/3807): Fix memory leak in postgresql_extensible.
 
 ## v1.5.2 [2018-01-30]
 

plugins/inputs/postgresql_extensible/postgresql_extensible.go

@@ -127,6 +127,8 @@ func (p *Postgresql) Gather(acc telegraf.Accumulator) error {
 		meas_name   string
 	)
 
+	p.AllColumns = nil
+
 	if p.Address == "" || p.Address == "localhost" {
 		p.Address = localhost
 	}